Berlin 2015 – scientific programme
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TT: Fachverband Tiefe Temperaturen
TT 20: Transport: Topological Insulators 1 (jointly with DS, HL, MA, O)
TT 20.7: Talk
Monday, March 16, 2015, 17:00–17:15, A 053
Spin texture of generic helical edge states — •Alexia Rod1, Thomas L. Schmidt2, and Stephan Rachel1 — 1Institut für Theoretische Physik, TU Dresden, Germany — 2Department of Physics, University of Basel, Switzerland
Edge states of time-reversal topological insulators can be described as helical Luttinger liquids. The generic helical liquid is the most general model of a time-reversal invariant helical liquid without axial spin symmetry. This symmetry is usually broken in experimental realizations, and it has been shown that its absence changes the transport properties significantly [1]. For a translation invariant system, the breaking of axial spin symmetry manifests itself in a momentum-dependent rotation of the spin quantization axis. Its manifestation in real space has remained, however, elusive so far.
Here we show that one can extract the rotation of spin quantization axis also in real space, e.g. for topological insulator disks with broken spin symmetry but also other geometries which are not rotationally invariant [2]. This suggests that the concept of a generic helical liquid is independent of the microscopic model and the considered geometry.
[1] T.L. Schmidt, S. Rachel, F. von Oppen, L. Glazman,
Phys. Rev. Lett. 108, (2012).
[2] A. Rod, T.L. Schmidt, S. Rachel, manuscript in preparation.